1. Field of the Invention
The present invention generally relates to an improved digital video signal processing system, and more particularly, to a video signal processing system well suited for a television receiver capable of reproducing high-quality color pictures from non-standard signals, such as reproduced signals from video tape recorders (VTR signals), which differ from standard signals.
2. Description of the Related Art
Owing to recent advances in digital techniques, research and development have been made for improvements in the quality of television pictures by utilizing image memories. An approach to improving the quality of television pictures involves luminance/chrominance signal (Y/C) separation and non-interlace conversion.
A technique is known wherein the Y/C separation in which a predetermined number of field memories are shared and the non-interlace conversion are simultaneously executed. Television receivers adopting such a technique can be of a smaller scale than television receivers designed to separately perform the Y/C separation and the non-interlace conversion.
However, when the television receivers, adapted for simultaneous execution of the Y/C separation and the non-interlace conversion, receive non-standard signals containing jitter in their synchronizing signals from video tape recorders (VTRs), the picture quality is considerably degraded. This is because the jitter causes the one-horizontal-line time of the VTR signals to differ so that it does not always equal an integral multiple of the color subcarrier frequency fsc.